They might be fed marshmallows and have knitted hammocks, but the brain-poisoned marmosets are also left essentially paralysed, mute, rigid and unable to groom or feed themselves. Yet the result is no more than a crude and simplistic model of Parkinson's disease that is completely unreliable in predicting human outcomes. Contrary to the extraordinary claims quoted in this article, today's most successful treatments for Parkinson's (levodopa, selegiline and apomorphine) were pioneered in human trials. Indeed, it is only by focusing on non-animal research that we can hope to move from treating Parkinson's disease to curing it.

Isobel Hutchinson

Animal Aid

Tonbridge

Kent

Face the facts, Theresa May

Nick Cohen correctly notes that evidence-free beliefs are frequently expressed in terms of feelings rather than facts ("In Mrs May's surreal world, feelings trump facts"). When the believer says "it feels" or "I feel that" (and then expresses a fact or thought rather than a feeling), they are masking their true feelings and voicing their opinion. The device is useful as "I feel" is difficult to argue with. The skill of unpacking beliefs, thoughts and opinions masquerading as feelings would promote an honest exchange of views and values. The real feelings of fear, anger, frustration and resentment that lie behind the public's reported opinions could be addressed openly and may even lead to honest debate.

Dr Anne Brockbank

London N1

Do try to contain yourself

A very interesting article from Harriet Meyer about the use of shipping containers as homes to battle the housing supply crises ("Would-be buyers home in on the DIY solution to Britain's housing crisis", Cash). However, this is nothing new. For many years, shipping containers have been used to house students in Amsterdam. For instance, there's Wenckenhof, a student campus consisting of 1,000 containers. The containers have all the mod-cons, plus a balcony or garden, and are indeed fun and comfortable to live in, judging by the long waiting list.

Willem de Blaauw

Amsterdam

New meaning to a close shave

Perhaps Jonathan Franzen ("The Kraus Project", New Review) might have done better to quote a snappier Karl Kraus prediction of our mobile phone intoxication. In 1909, in an essay called Reforms, Kraus re-enacts the advent of the safety razor to exemplify a modernist "reform". As the new gadget privatises the function of shaving and removes it from the social encounter of the barber's shop, he mock-laments the spiritual void of the customer deprived of the barber's pamperings and chatter, but proposes a mock-resolution: the invention of a talking razor, capable, at the press of a button, of reciting all the unsolicited pleasantries of a barber – the stuff that was anathema to the satirist. Who says Kraus wasn't a modernist?

Gilbert Carr

Stillorgan,

Co Dublin

Not easy to save the children

Your letters page headline was half right ("We all have a duty to step in when the young are in danger", Big Issue). In the immediate postwar period, the general public still felt a collective duty towards local children. Consider how different things may have been for poor James Bulger – and his abductors – had several adults challenged them.

By then, however, the disastrously counterproductive "Stranger Danger" campaign had resulted in most adults choosing to keep away from any children unknown to them. Fearing false accusation, adults still stay aloof even when a child might possibly be in danger. It is not easy to see how some form of in loco parentis can be restored.

Alan Hallsworth (professor emeritus)

Portsmouth

BBC can learn from X Factor

Barbara Ellen rightly applauds the broad ethnic mix of ITV's The X Factor ("Huge plaudits for the X-Factor's colour-blindness", Comment). The BBC's Strictly Come Dancing is careful to include at least one ethnic minority celebrity in each series. But of 38 professional dancing coaches from many countries featured over 11 series, not one has been black or non-white.